Project Summary The main goal of this revised application is to purchase a high-performance MALDI ToF/ToF mass spectrometer at the University of Puerto Rico, Molecular Science Research Center (MSRC). Planning of this instrumentation proposal has brought together 16 scientists from three research centers (UPR-Rio Piedras, UPR-Medical Sciences and Institute of Neurobiology in San Juan) in a common effort to enhance our Mass Spectrometry and Proteomic facilities at the MSRC (http://cicim.upr.edu/). The user base of our Mass Spectrometry and Proteomic facilities has become increasingly large and interdisciplinary, thus placing more demands in terms of the variety of services and applications that must be provided. To meet these demands, and to maintain a competitive facility, we propose to acquire a new MALDI ToF/ToF mass spectrometer. After careful evaluation of the different MALDI ToF/ToF mass spectrometers in the market, we determined that the best instrument to fulfill our research and R&D needs at the MSRC is the MALDI- 7090 from Shimadzu. Furthermore, in the years to come, we feel that the application scientists from Shimadzu will help us to develop novel methods as the MS field evolves, which will be critical to stay abreast with the scientific challenges ahead. This instrument will impact a list of research projects and new grant applications that include biologically relevant studies such as the development of an HIV-1 Env protein as a vaccine candidate, HIV-associate dementia studies, regulation of the EGFR signaling in inflammatory breast cancer, using lipidomic analysis of acetylcholine receptor detergent-complexes to enhance its crystallization, development of nanomaterials for water purification, neuropeptide characterization in schistosomiasis and development of anticancer drug delivery agents. The proposed upgrade will serve to foster and strengthen collaborative and multidisciplinary collaborations among investigators at the MSRC and other institutions inside and outside Puerto Rico. Another important aspect for the development of these Mass Spectrometry Facility is the service that this facility can provide to researchers who will be recruited to pursue basic and biomedical relevant projects at UPR in the near future. In addition, the upgraded facility will enhance faculty's, postdoctoral fellows' and graduate students? knowledge and skills required for competitive research. Finally, this upgrade will impact the development of a large population of students that are currently supported by fellowships or assistantships provided by NIH, NASA, and NSF sponsored programs.